script_scanner.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "../stdafx.h"
#include "../debug.h"
#include "../string_func.h"
#include "../settings_type.h"
 
#include "../script/squirrel.hpp"
#include "script_scanner.hpp"
#include "script_info.hpp"
#include "script_fatalerror.hpp"
 
#include "../network/network_content.h"
#include "../3rdparty/md5/md5.h"
#include "../tar_type.h"
 
#include "../safeguards.h"
 
bool ScriptScanner::AddFile(const std::string &filename, size_t, const std::string &tar_filename)
{
  this->main_script = filename;
  this->tar_file = tar_filename;
 
  auto p = this->main_script.find_last_of(PATHSEPCHAR);
  this->main_script.erase(p != std::string::npos ? p + 1 : 0);
  this->main_script += "main.nut";
 
  if (!FioCheckFileExists(filename, this->subdir) || !FioCheckFileExists(this->main_script, this->subdir)) return false;
 
  this->ResetEngine();
  try {
    this->engine->LoadScript(filename);
  } catch (Script_FatalError &e) {
    Debug(script, 0, "Fatal error '{}' when trying to load the script '{}'.", e.GetErrorMessage(), filename);
    return false;
  }
  return true;
}
 
ScriptScanner::ScriptScanner() :
  engine(nullptr)
{
}
 
void ScriptScanner::ResetEngine()
{
  this->engine->Reset();
  this->engine->SetGlobalPointer(this);
  this->RegisterAPI(this->engine);
}
 
void ScriptScanner::Initialize(const char *name)
{
  this->engine = new Squirrel(name);
 
  this->RescanDir();
 
  this->ResetEngine();
}
 
ScriptScanner::~ScriptScanner()
{
  this->Reset();
 
  delete this->engine;
}
 
void ScriptScanner::RescanDir()
{
  /* Forget about older scans */
  this->Reset();
 
  /* Scan for scripts */
  this->Scan(this->GetFileName(), this->GetDirectory());
}
 
void ScriptScanner::Reset()
{
  for (const auto &item : this->info_list) {
    delete item.second;
  }
 
  this->info_list.clear();
  this->info_single_list.clear();
}
 
void ScriptScanner::RegisterScript(ScriptInfo *info)
{
  std::string script_original_name = this->GetScriptName(info);
  std::string script_name = fmt::format("{}.{}", script_original_name, info->GetVersion());
 
  /* Check if GetShortName follows the rules */
  if (info->GetShortName().size() != 4) {
    Debug(script, 0, "The script '{}' returned a string from GetShortName() which is not four characters. Unable to load the script.", info->GetName());
    delete info;
    return;
  }
 
  if (this->info_list.find(script_name) != this->info_list.end()) {
    /* This script was already registered */
#ifdef _WIN32
    /* Windows doesn't care about the case */
    if (StrEqualsIgnoreCase(this->info_list[script_name]->GetMainScript(), info->GetMainScript())) {
#else
    if (this->info_list[script_name]->GetMainScript() == info->GetMainScript()) {
#endif
      delete info;
      return;
    }
 
    Debug(script, 1, "Registering two scripts with the same name and version");
    Debug(script, 1, "  1: {}", this->info_list[script_name]->GetMainScript());
    Debug(script, 1, "  2: {}", info->GetMainScript());
    Debug(script, 1, "The first is taking precedence.");
 
    delete info;
    return;
  }
 
  this->info_list[script_name] = info;
 
  if (!info->IsDeveloperOnly() || _settings_client.gui.ai_developer_tools) {
    /* Add the script to the 'unique' script list, where only the highest version
     *  of the script is registered. */
    auto it = this->info_single_list.find(script_original_name);
    if (it == this->info_single_list.end()) {
      this->info_single_list[script_original_name] = info;
    } else if (it->second->GetVersion() < info->GetVersion()) {
      it->second = info;
    }
  }
}
 
void ScriptScanner::GetConsoleList(std::back_insert_iterator<std::string> &output_iterator, bool newest_only) const
{
  fmt::format_to(output_iterator, "List of {}:\n", this->GetScannerName());
  const ScriptInfoList &list = newest_only ? this->info_single_list : this->info_list;
  for (const auto &item : list) {
    ScriptInfo *i = item.second;
    fmt::format_to(output_iterator, "{:>10} (v{:d}): {}\n", i->GetName(), i->GetVersion(), i->GetDescription());
  }
  fmt::format_to(output_iterator, "\n");
}
 
struct ScriptFileChecksumCreator : FileScanner {
  MD5Hash md5sum; 
  Subdirectory dir; 
 
  ScriptFileChecksumCreator(Subdirectory dir) : dir(dir) {}
 
  /* Add the file and calculate the md5 sum. */
  bool AddFile(const std::string &filename, size_t, const std::string &) override
  {
    Md5 checksum;
    uint8_t buffer[1024];
    size_t len, size;
 
    /* Open the file ... */
    auto f = FioFOpenFile(filename, "rb", this->dir, &size);
    if (!f.has_value()) return false;
 
    /* ... calculate md5sum... */
    while ((len = fread(buffer, 1, (size > sizeof(buffer)) ? sizeof(buffer) : size, *f)) != 0 && size != 0) {
      size -= len;
      checksum.Append(buffer, len);
    }
 
    MD5Hash tmp_md5sum;
    checksum.Finish(tmp_md5sum);
 
    /* ... and xor it to the overall md5sum. */
    this->md5sum ^= tmp_md5sum;
 
    return true;
  }
};
 
static bool IsSameScript(const ContentInfo *ci, bool md5sum, ScriptInfo *info, Subdirectory dir)
{
  uint32_t id = 0;
  const char *str = info->GetShortName().c_str();
  for (int j = 0; j < 4 && *str != '\0'; j++, str++) id |= *str << (8 * j);
 
  if (id != ci->unique_id) return false;
  if (!md5sum) return true;
 
  ScriptFileChecksumCreator checksum(dir);
  auto tar_filename = info->GetTarFile();
  TarList::iterator iter;
  if (!tar_filename.empty() && (iter = _tar_list[dir].find(tar_filename)) != _tar_list[dir].end()) {
    /* The main script is in a tar file, so find all files that
     * are in the same tar and add them to the MD5 checksumming. */
    for (const auto &tar : _tar_filelist[dir]) {
      /* Not in the same tar. */
      if (tar.second.tar_filename != iter->first) continue;
 
      /* Check the extension. */
      const char *ext = strrchr(tar.first.c_str(), '.');
      if (ext == nullptr || !StrEqualsIgnoreCase(ext, ".nut")) continue;
 
      checksum.AddFile(tar.first, 0, tar_filename);
    }
  } else {
    /* There'll always be at least 1 path separator character in a script
     * main script name as the search algorithm requires the main script to
     * be in a subdirectory of the script directory; so <dir>/<path>/main.nut. */
    const std::string &main_script = info->GetMainScript();
    std::string path = main_script.substr(0, main_script.find_last_of(PATHSEPCHAR));
    checksum.Scan(".nut", path);
  }
 
  return ci->md5sum == checksum.md5sum;
}
 
bool ScriptScanner::HasScript(const ContentInfo *ci, bool md5sum)
{
  for (const auto &item : this->info_list) {
    if (IsSameScript(ci, md5sum, item.second, this->GetDirectory())) return true;
  }
  return false;
}
 
const char *ScriptScanner::FindMainScript(const ContentInfo *ci, bool md5sum)
{
  for (const auto &item : this->info_list) {
    if (IsSameScript(ci, md5sum, item.second, this->GetDirectory())) return item.second->GetMainScript().c_str();
  }
  return nullptr;
}